The present invention relates to a front structure of a vehicle that includes two side members extending in the front-rear direction of the vehicle.
In general, a vehicle includes two side members and a bumper beam in the front section. The two side members extend in the front-rear direction of the vehicle. The bumper beam extends in the lateral direction of the vehicle in front of the side members and is fixed to the side members.
In a frontal collision of the vehicle, most of the collision energy is transferred to the side members through the bumper beam and absorbed by the side members.
When a section of the vehicle that is located outward from a side member in the lateral direction of the vehicle collides with a pole-shaped obstacle such as a power pole or a signpost, the side member may not be able to absorb the collision energy in a preferred manner.
To solve this problem, Japanese Laid-Open Patent Publication No. 2012-228907 discloses a vehicle front structure in which each of the side members includes a first projection extending outward in the lateral direction of the vehicle from the side section of the side member. In addition, the bumper beam includes bumper beam extensions on opposite ends of the bumper beam. Each bumper beam extension extends outward in the lateral direction of the vehicle and includes a second projection extending toward the corresponding first projection.
When the section of the vehicle that is located laterally outward from the side member, namely, the bumper beam extension, collides with a pole-shaped obstacle, the bumper beam extension moves rearward, and the second projection of the bumper beam extension abuts against the first projection extending from the side member. The abutment of the second projection against the first projection transfers the collision energy applied to the bumper beam extension to the side member through the first and second projections.
In general, a bumper beam is hollow to absorb some of the collision energy and to reduce the weight of the bumper beam. However, the following problem may arise when such a hollow bumper beam includes a transfer portion that transfers collision energy like the second projection of the '907 publication. When absorbing collision energy, the end of the bumper beam undergoes plastic deformation that crushes the cross-sectional shape of the bumper beam. In addition, the transfer portion moves rearward together with the bumper beam and abuts against a side member. That is, the cross-sectional shape of the bumper beam is crushed to some extent before the transfer portion abuts against the side member. Thus, the transfer of collision energy to the side member through the transfer portion is delayed. This, in turn, delays the transfer of the collision energy from the side member through a mount to the engine and the transmission. As a result, it becomes difficult to quickly move the vehicle away from the obstacle.